Eliminate most uses of the old methods.
To continue on this path, once we agree the new methods make sense,
the next step is to rename cricket::VideoFrame::GetVideoFrameBuffer
--> video_frame_buffer, to match the name in webrtc::VideoFrame (if we
think that name is ok?). And then start updating all code to access
planes via the VideoFrameBuffer, and delete corresponding methods in
both cricket::VideoFrame and webrtc::VideoFrame.
BUG=webrtc:5682
Review URL: https://codereview.webrtc.org/1878623002
Cr-Commit-Position: refs/heads/master@{#12407}
06176e49e2